Importance: Little is known about the effect of race/ethnicity on the incidences of Graves’ disease and Hashimoto’s thyroiditis.
Methods: We assessed autoimmune thyroid disease incidence in U.S. active duty service personnel aged 20-54 years from 1997-2011 (20,270,688 person years), calculating the direct age-standardized incidence and incidence rate ratios (IRR) for women and men by self-reported race/ethnicity.
Results: For Graves’ disease, the incidence was almost two times greater in African American women (IRR=1.92 [1.56-2.37]) and Asian/Pacific Islanders (IRR=1.78 [1.20-2.66]) than in Caucasian women. Similarly, the incidence was over two times greater in African American men (IRR=2.53 [2.01-3.18]) and Asian/Pacific Islanders (IRR=3.36 [2.57-4.40]) than in Caucasian men. For Hashimoto’s thyroiditis, on the contrary, Caucasians had the highest incidence in both women (for African Americans, IRR=0.43 [0.29-0.63], and 0.42 [0.20-0.90] for Asian/Pacific Islanders) and men (for African Americans, IRR=0.22 [0.11-0.47], and 0.23 [0.07-0.72] for Asian/Pacific Islanders). Women were 4.98 (4.31-5.74) and 7.86 (6.44-9.59) times more likely than men to have Graves’ disease and Hashimoto thyroiditis, respectively. The incidence of both diseases increased with age in women and men (P≤ 0.032).
Conclusions and significance: The incidence of Graves’ disease and Hashimoto’s thyroiditis varies substantially by race/ethnicity. This presentation will also discuss follow-on work examining whether these patterns are seen in the wider U.S. population.
Recognizing racial differences in autoimmune thyroid disease is key to understanding why it occurs. We don’t yet know whether the differences seen are due to genetics, environmental exposures, or a combination of both. Finding the root causes of thyroid autoimmunity has the potential to lead to prevention of thyroid disorders, and may also lead to crucial insights into other autoimmune disease.